The effects of arable field margin management on the abundance and species richness of Araneae (spiders)

The effects of ten different management regimes on the abundance and species richness of Araneae on pre-existing and newly expanded zones of field margins surrounding arable fields are compared in a large-scale experiment conducted between 1987 and 1991. Most of the management regimes involved varying the Liming and frequency with which the field margins were cut. There was no evidence of consistent temporal trends in the abundance and species richness of Araneae on either the existing or expanded zones of the field margins during the first four years of the experiment. However, lowest numbers were recorded before expansion of the margins in 1987, and highest numbers in the final sample, in 1991. Araneae remained less abundant, and less species rich, on the newly expanded than on the existing zones of the field margins four years after they were set-aside'. Culling reduced both abundance and species richness. Regimes which included culling in mid-summer had a greater impact which persisted for longer than did those involving cutting in spring and autumn. Removal of cut material was associated with lower species richness than leaving it in situ. Sowing the margins with a wild flower seed mixture was associated with increased abundance and species richness of Araneae. Annual spraying with a broad-spectrum, non-persistent herbicide reduced the abundance of Araneae but the effect was not detectable until several months after the application of the spray. Both the species richness and abundance of Araneae were positively correlated with a measure of vegetation height made on the field margins in September, on both the pre-existing and newly expanded zones of the margins. The extent to which management practices which benefit Araneae are compatible with both the management requirements for various other taxa. and the overriding constraint of effective pernicious weed control on field margins, is discussed.     

A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography

High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44-49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 μm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers.     

Broad patterns of speciation are correlated with the evolution of new silk proteins in spiders but not in the lepidoptera

Silk synthesis is an ancestral character of both the Lepidoptera and the Araneae. Araneae evolution is marked by an increased commitment to a silk-producing physiology. At least three major Araneae speciation events are correlated with the evolution of new silk-producing glands and new silk proteins. In contrast, although 98% of the Lepidoptera produce silk, there appears to be no relationship between silk use, protein types, and species numbers. The differences in these two systems, both meeting a need to produce a large volume of protein, may reflect predictable resource availability to herbivorous Lepidoptera larvae but fluctuating resource availability to carnivorous spiders.     

Effect of boundary type and season on predatory arthropods associated with field margins on New Zealand farmland

Pitfall traps were used to monitor predatory arthropod numbers along two types of field boundary, a post and wire fence line and a Cupressus macrocarpa hedge, along the same paddock margin in Canterbury, New Zealand, over 24 months. The seven most abundant predator groups recorded were: Araneae > Phalangiidae > Staphylinidae > Coccinellidae > Chilopoda > Hemerobiidae > Carabidae. Araneae, Phalangiidae, Staphylinidae, Chilopoda and Hemerobiidae were found in larger numbers at the wire fence than at the hedge site, whereas the numbers of Carabidae and Coccinellidae adults exhibited no field margin preference. However, more species of Araneae and Staphylinidae were caught at the hedge site, whereas species richness of carabid beetles was greatest at the wire fence. Principal component analysis clearly separated the samples collected from the two habitats based on the assemblages of Araneae, Staphylinidae and Carabidae, and certain species in each of these taxonomic groups appeared to be particularly associated with one boundary type or the other. All the main taxonomic groups exhibited clear seasonal patterns, with distinct peaks in abundance occurring at certain times of the year. The results of the study reinforce the idea that management of field boundaries can be used to manipulate the type and abundance of particular groups of predatory arthropods, and that seasonal patterns should be taken into account in schemes of integrated pest management so that any adverse effects of biocide application on these beneficial species may be minimised.     

Spiders in Upper Cretaceous Amber from New Jersey (Arthropoda: Araneae)

The oldest described fossils of the extant spider families Segestriidae, Oonopidae, Oecobiidae, Dictynidae and Linyphiidae, previously known from the Tertiary, are presented from Upper Cretaceous amber of New Jersey. The third and oldest known specimen of the fossil spider family Lagonomegopidae is also described and provides further palaeontological evidence of a common Laurasian fauna. The extant genera Segestria and Oecobius are taken back a further 52 and 69–74 myr respectively in the fossil record. These fossils predict the presence of the Caponiidae, Tetrablemmidae, Orsolobidae, Dysderidae, Hersiliidae, Eresidae, Pimoidae, Scytodoidea s.l. , cyatholipoids, theridioids and symphytognathoids in the Cretaceous. They also extend the known geological range of extant spider families through and beyond the end–Cretaceous extinction. This event, which affected numerous marine and some terrestrial organisms, probably had little effect on the Araneae.     

The accoutrements of spiders' eggs (Araneae) with an exploration of their functional importance

Analysis is presented of the characteristics of spheres coating the chorion surface of the eggs from 41 species belonging to 15 families of spiders. Examples of eggs from the arachnid orders Opiliones, Amblypygi and Uropygi are illustrated for the first time. The spheres are unique, among arachnids, to the Araneae. Their form and size class distributions overlap considerably between families and the spheres are present in all 22 families of Araneae that have been examined; they represent a very conservative morphological feature in the evolution of the Araneae. Evidence of specialized regions of the egg surface (micropyllar areas and plastrons) was found only in an opilionid. As spiders' eggs are laid in silk egg sacs, mostly in clutches, the possible effects of these characteristics are discussed from evidence in the literature and from a functional theoretic stance.     

The adequacy of collecting techniques for estimating species richness of grassland invertebrates

1.  There is still considerable debate about the most effective methods of sampling invertebrates in monitoring and assessment programmes.
2.  The above-ground invertebrates of a limestone grassland in north-east England were compared between samples from pitfall traps and from a D-vac suction trap combined with a lightweight swish net (SW/DV).
3.  Over 14 000 individuals were captured, with similar numbers in the pitfall and SW/DV samples. A total of 480 species of Hemiptera, Coleoptera, Diptera and Araneae was identified and placed into 14 taxa for further analysis.
4.  The pitfall sample produced species/specimen curves from which it was possible to estimate species richness for all the Coleoptera and Araneae taxa and the calypterate Schizophora. The SW/DV sample was adequate to estimate the species richness of Hemiptera, most Diptera taxa, herbivorous Coleoptera and Linyphiidae.
5.  The proportion of Coleoptera and Araneae taxa that were method-unique was higher in the pitfall sample than the SW/DV sample and vice versa for the Hemiptera and Diptera taxa. Nevertheless, a relatively high proportion of method-unique species of most taxa was found in both sample types, indicating that they can each contribute to assessing species assemblages in grasslands.
6.  Both pitfall traps and SW/DV samples are needed to estimate species richness in grasslands for all taxa except Heteroptera, Homoptera and Lycosidae. Herbivorous Coleoptera and Linyphiidae were collected in numbers adequate for assessing richness in both sample types, but more specimens were required in one or other sample for the remaining taxa.     

Predatory fauna in cornfields and response to imidacloprid seed treatment

The composition and abundance of predatory fauna in corn, Zea mays L., were studied by field visual sampling and pitfall traps over a 5-yr period. In visual samplings, the most abundant groups were Araneae, Heteroptera, Carabidae, Coccinellidae, and Staphylinidae, whereas the prevalent predators caught in pitfall traps belonged to Carabidae, Araneae, Dermaptera, and Opilionidae. The most abundant species or genera in the prevalent groups, except in Arachnida, were identified. Application of the insecticide imidacloprid as a seed dressing is common in the study area to prevent wireworm and cutworm damage. By comparing predator composition and abundance in treated and untreated cornfields during the 5 yr, we assessed the impact of imidacloprid seed treatment on predatory fauna. Among the prevalent predator groups found in visual sampling, Araneae, Coccinellidae, and Staphylinidae were not affected by the imidacloprid treatment, whereas Carabidae was only moderately affected in one of the 5 yr studied. On the contrary, Heteroptera was more drastically reduced by the imidacloprid, but the effect varied with the year. Incidence of European corn borer, Ostrinia nubilalis (Hübner), may be increased as result of such heteropteran reduction. In pitfall traps, only Staphylinidae resulted in lower numbers as consequence of the treatment, whereas the rest of the most abundant predator groups, Carabidae, Araneae, Dermaptera, Opilionidae, Trombididae, and Heteroptera, were not caught in significantly different numbers in treated or untreated plots.     

海南细长莱蛛（蜘蛛目：巨蟹蛛科）的雌性新发现

本文首次报道了细长莱蛛Rhitymna macilenta Quan＆Liu2012的雌性,该标本采自海南岛黎母山国家自然保护区,标本保存于湖北大学生命科学学院动物行为与进化中心。细长莱蛛Rhityrmna macilenta Quan＆Liu2012（图1—3）鉴别特征：该种雌蛛可根据其身体苍白,外雌器中板巨大和受精管简单等特征与该属其它种区分。     

云南永仁更新世初期哺乳动物化石

本文记述了1974年和1978年两次在云南永仁盆地湖相地层中两个化石地点发现的四种哺乳类化石,犀牛一种,象类化石三种。同时讨论了昭通剑齿象的地质时代,记述了一新种嵌齿象。永仁化石层可与毗邻的元谋盆地“元谋组”对比,时代为更新世初期。     

Elevation and experimental snowmelt manipulation affect emergence phenology and abundance of soil‐hibernating arthropods

1. Effects of climate change, such as higher average temperatures and earlier snowmelt, are already apparent, especially in alpine regions. However, community responses of functionally important arthropod taxa to changing climatic conditions are mostly unknown. 2. In this study, an earlier snowmelt was simulated at 15 plots along an elevational gradient in the German Alps. At each study site, soil emergence traps were established for sampling soil‐hibernating arthropods on earlier and control snowmelt treatments during the growing season. The abundance and emergence phenology of the five most common arthropod orders (Araneae, Coleoptera, Diptera, Hemiptera, Hymenoptera) were analysed, as well as the species richness of Coleoptera. 3. There was increasing abundance and species richness of Coleoptera along the elevational gradient, indicating that at higher altitudes more individuals and species hibernate in the soil. Abundances of Diptera also increased with elevation. By contrast, abundances of Hemiptera declined with increasing elevation, while abundances of Araneae and Hymenoptera did not show significant elevational patterns. Arthropods at higher elevations emerged, on average, 5 weeks later than arthropods at lower elevations, because of a longer‐lasting snow cover. The earlier snowmelt treatment resulted in higher abundances of Araneae and Hymenoptera compared with the control plots, indicating that the time of snowmelt influenced the abundance of predators, such as spiders or parasitic wasps, more than that of herbivores. 4. An earlier emergence of certain arthropod guilds and a change in relative abundance of guilds might desynchronise species interactions, leading to a possible loss of biodiversity.     

Partially incorrect fossil data augment analyses of discrete trait evolution in living species

Ancestral state reconstruction of discrete character traits is often vital when attempting to understand the origins and homology of traits in living species. The addition of fossils has been shown to alter our understanding of trait evolution in extant taxa, but researchers may avoid using fossils alongside extant species if only few are known, or if the designation of the trait of interest is uncertain. Here, I investigate the impacts of fossils and incorrectly coded fossils in the ancestral state reconstruction of discrete morphological characters under a likelihood model. Under simulated phylogenies and data, likelihood-based models are generally accurate when estimating ancestral node values. Analyses with combined fossil and extant data always outperform analyses with extant species alone, even when around one quarter of the fossil information is incorrect. These results are especially pronounced when model assumptions are violated, such as when there is a trend away from the root value. Fossil data are of particular importance when attempting to estimate the root node character state. Attempts should be made to include fossils in analysis of discrete traits under likelihood, even if there is uncertainty in the fossil trait data.     

A new species of the genus <Emphasis Type="Italic">Synema Simon</Emphasis>, 1864 (Araneae: Thomisidae) from Turkey

Synema anatolica sp. n. (Araneae: Thomisidae) is described based on both sexes from Turkey. Differences between the new species and related species are discussed.     

A statistical/computer-graphic technique for assessing variation in tectonically deformed fossils and its application to Cambrian trilobites from Kashmir

Hughes, N. C. & Jell, P. A. 1992 07 15: A stdlislical/compuler-graphic technique for assessing variation in tectonically deformed fossils and its application to Cambrian trilobites from Kashmir.
A combined approach using statistics and computer graphics can help resolve patterns of morphological variation in tectonically deformed fossils. Bivariate analyses and Principal Components Analysis can be used to identify a generalized strain vector in populations of deformed fossils, the identification of which permits discrimination of biological and tectonically induced variation. Results can be used to determine the number of taxa and growth relationships within the population. Statistically resolved taxa can be compared with species described from other areas using computer-aided shape restorations. Application of these techniques to a sample of trilobite cranidia from the Cambrian of Kashmir demonstrates that the variation of characters used to diagnose several genera and species are ontogeny- or deformation-controlled. Seven previously described species of Saukia, Prosaukia, Hundwarella and Anomocare are best considered as a single species, Hundwarella personara . These results suggest a Middle Cambrian age for the fauna, which has affinities with other faunas described from India and northern China. Hundwarella personara shows a pattern of developmental flexibility similar to that seen in other Cambrian trilobites. Morphometrics, computer-aided restoration, deformed fossils, allometry, trilobites, Cambrian, Kashmir, developmental flexibility .     

Successful overwintering of arthropods in roadside verges

In densely populated areas, roadside verges often provide the last semi-natural habitats available. Their ecological value is often stressed by bio survey results. Yet insect summer surveys potentially misjudge the value of a biotope (roadside or otherwise) since the occurrences of species may only be seasonal, or even transient. To effectively ascertain the importance of a site for insects, species must be shown to complete their life cycle there or at least be shown to successfully accomplish critical life stages, such as reproduction or overwintering. To confirm overwintering of arthropods in roadsides, sods were cut in late winter in a verge where several years of summer survey data were available. The sods were placed in transparent semi-permeable cages and kept alive during subsequent spring, summer and autumn. All emerging arthropods were caught inside the cages using pitfall and funnel traps and identified to order or family level. Most of the terrestrial arthropod phyla and orders occurring in NW-Europe appeared to be represented. Several groups were further identified to the species level: Carabidae (Coleoptera), Curculionidae (Coleoptera), Araneae, Orthoptera, Apidae (Hymenoptera), Syrphidae (Diptera) and Dephacidae/Cercopidae (Hemiptera). Particularly for the Carabidae, Araneae and Curculionidae, many species recorded in summer were also found to overwinter; species overlap amounted to approximately 67%. Rarefaction of the summer sample or excluding possible summer vagrants, raised this overlap to as much as 88% for the Carabidae. Many of the species successfully overwintering in the roadside verge were generalists, but less common, more stenotopic species were present as well. Not only species hibernating as adults were involved, but also species overwintering in immature stages, indicating reproduction also takes place in the roadside verge. Apparently the roadside occurrence of many arthropod species, including stenotopic and declining ones, is not merely seasonal or incidental, and roadside verges do not necessarily act as a sink only. The ecological importance often attributed to roadside verges should clearly be taken seriously.     

海南儋州地区果园蜘蛛种类调查研究初报

通过调查研究,共发现海南儋州地区果园蜘蛛48种,隶属12科,35属。其中,有15种分布于荔枝园,32种分布于芒果园,2种分布于龙眼园,1种分布于番石榴上。拟盲幽灵蛛Pholcus opilionoides与梅氏新园蛛Neoscona melloteei在芒果和荔枝上都有分布。有6个标本只鉴定到属。     

广西大新黑洞哺乳动物化石

<正> 本文研究的材料是1955年初,由裴文中教授领导的野外考察队在广西大新、武鸣、柳州、崇左、扶绥等县进行古人类和第四纪哺乳动物洞穴调查时发现的。这批材料发现于大新县正隆乡牛睡山黑洞(野外编号:5657),计有巨猿等多种哺乳动物化石。巨猿牙齿化石已由裴文中、吴汝康共同研究并于1956年发表了专题报告。报告中曾提到,与巨猿同时发现的其它哺乳类化石有猩猩、大熊猫、剑齿象和巨獏等,其地质时代为更新世中期。     

Liaoxia Cao et S.Q. Wu (Gnetales): ephedroids from the Early Cretaceous Yixian Formation in Liaoning, northeastern China

Gnetalean compression-impression fossils are described from the Early Cretaceous Yixian Formation, Liaoning Province, north-eastern China, and assigned to six species of Liaoxia Cao et S.Q. Wu. The fossils have opposite-decussate phyllotaxis and cones comprising 2–12 pairs of bracts. Ovulate cones have seeds typically in a distal position. The species differ from each other and from previously described fossils in the absence or presence of leaves, shape of cones and seeds, and shape and position of cone bracts. The species of Liaoxia are probably close relatives of extant species of Ephedra L., but diagnostic reproductive details that could confirm this hypothesis are not preserved. The restricted information in the fossils and the poorly understood morphological diversity of extant Ephedra, prevent assignment of the fossils to any particular subgroup of Ephedra, as well as an explicit exclusion of them from the extant genus.     

Niche modelling of the Chilean recluse spider Loxosceles laeta and araneophagic spitting spider Scytodes globula and risk for loxoscelism in Chile

In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider Loxosceles laeta (Nicolet) (Araneae: Sicariidae). It is predated by the spitting spider Scytodes globula (Nicolet) (Araneae: Scytodidae). The biology of each of these species is not well known and it is important to clarify their distributions. The aims of this study are to elucidate the variables involved in the niches of both species based on environmental and human footprint variables, and to construct geographic maps that will be useful in estimating potential distributions and in defining a map of estimated risk for loxoscelism in Chile. Loxosceles laeta was found to be associated with high temperatures and low rates of precipitation, whereas although S. globula was also associated with high temperatures, its distribution was associated with a higher level of precipitation. The main variable associated with the distribution of L. laeta was the human footprint (48.6%), which suggests that this is a highly invasive species. Similarly to other species, the distribution of L. laeta reaches its southern limit at the Los Lagos region in Chile, which coincides with high levels of precipitation and low temperatures. The potential distribution of L. laeta in Chile corresponds to the distribution of cases of loxoscelism.     

中国云南潮狼蛛属1新种(蜘蛛目:狼蛛科)

本文记述了采白云南的獾蛛属Hygrolycosa Dahl,1908 1新种Hygrolycosa ligulacea sp.nov..并提供了详细的描述、鉴别特征图版和地理分布数据.模式标本保存在湖南师范大学生命科学学院,部分副模保存于美同加州科学院. Abstract： One new wolf spider of the genus Hygrolycosa Dalal, 1908 (Araneae: Lycosidae) from China is described and illustrated, under the name of Hygrolycosa ligulacea sp. nov.. The differences among new species and its related species are discussed, Distributional data and illustrations of body and genital organs are provided.